Improving geometric accuracy in the presence of susceptibility difference artifacts produced by metallic implants in magnetic resonance imaging

• Published in: IEEE transactions on medical imaging Vol. 24; no. 10; pp. 1387 - 1399
• Main Authors: Pauchard, Y., Smith, M.R., Mintchev, M.P.
• Format: Journal Article
• Language: English
• Published: United States IEEE 01-10-2005; The Institute of Electrical and Electronics Engineers, Inc. (IEEE)
• Subjects: Algorithms; Distortion compensation; Electric Impedance; Image Enhancement - methods; Image Interpretation, Computer-Assisted - methods; Image registration; Imaging phantoms; Imaging, Three-Dimensional - methods; Impedance; Implants; Magnetic resonance imaging; Magnetic Resonance Imaging - instrumentation; Magnetic Resonance Imaging - methods; Magnetic susceptibility; metallic implants; Metals; Phantoms, Imaging; Prostheses and Implants; Reproducibility of Results; Sensitivity and Specificity; Spline; Surgery; susceptibility artifacts; Testing; Thigh; thin-plate splines; Transplants & implants
• ISSN: 0278-0062; 1558-254X
• DOI: 10.1109/TMI.2005.857230

Geometric and intensity distortions due to the presence of metallic implants in magnetic resonance imaging impede the full exploitation of this advanced imaging modality. The aim of this study is to provide a method for (a) quantifying and (b)reducing the implant distortions in patient images. Initially, a set of reference images (without distortion) was obtained by imaging a custom-designed three-dimensional grid phantom. Corresponding test images (containing the distortion) were acquired with the same imaging parameters, after positioning a specific metallic implant in the grid phantom. After determining: 1) the nonrecoverable; 2) the distorted, but recoverable; and 3) the unaffected areas, a point-based thin-plate spline image registration algorithm was employed to align the reference and test images. The calculated transformation functions utilized to align the image pairs described the implant distortions and could therefore be used to correct any other images containing the same distortions. The results demonstrate successful correction of grid phantom images with a metallic implant. Furthermore, the calculated correction was applied to porcine thigh images bearing the same metallic implant, simulating a patient environment. Qualitative and quantitative assessments of the proposed correction method are included.